New Planer, New Jig, New Problem

A while back I made a jig that allowed me to sharpen my planer and jointer knives.  Recently I bought a new planer (Dewalt 735) and therefore I needed a new jig (larger knives).  You can purchase the plans here.  The new planer presented a new problem – indexing pins!  The new planer uses indexing pins on the cutter-head in order to consistently position all three knives.  The old planer used springs to push the knives up from below and a setting jig to seat them the correct distance from the cutter-head surface -which was perfect for setting newly sharpened knives!  Had I known the new planer used indexing pins I would NOT have purchased this planer.

Solution? I am thinking of elongating the holes in the knives and using a setting jig (yet to be designed) to seat the knives the proper distance from the cutter-head surface.  In theory this should work.  One of my fears is that the pins might be serving two purposes – indexing and holding the knives still under load.  I’m hoping the clamp that secures the knives to the cutter-head is adequate.

Your thoughts??

Picture of cutter-head with knife on w/o clamp and screws showing the indexing pin protruding through the knife.

(click image to enlarge)

5 Responses to “New Planer, New Jig, New Problem”

  1. Mark Going says:

    I have the Dewalt 734, which uses very similar knives. To hone them, I set two 1/4″ dowels into the edge of a 3/4 x 3 x 13″ long purple heart board. I trimmed the dowels to 1/16″ length. The dowels are indexed to the 2nd outer screw holes on the knives.

    Instead of honing the bevel, I hone the flat side of the blade by pressing down on the blade with the jig on wet/dry paper on a granite block. To get as even a material removable as possible, I start with the worst knife in the set and count the strokes, using the same number in each knife on each grade of paper up to 2000 grit.

    A bit laborious (like flattening the back of a hand plane iron), I have been able to successsfully rehone a couple times on the 3 sets of blades I have. So far I have not exceeded the blades’ ability to cut well, probably because I am only removing a few thousandths inch of material from the blades’ thickness

    Note, it will not remove any deep nicks, but by changing blade orientation, their effect is minimized.

    Just an idea that you may be able to improve on.

  2. andrew says:

    Not sure I understand the problem, is it that the sharpening jig no longer works? or that the pins don’t allow for proper spacing?

    If it’s the former, I’d suggest cutting holes or slots to support the indexing pins…

    But if its the later (which I suspect it is) I’m not sure you’d want to play with the blades. Theoretically, the wear on all the cutters is equal, as is the sharpening. Narrower blades from use and sharpening should be the same on all of them, meaning you just need to get closer to the wood to plane it. The cutting depth gauge might be off, but I’ve never found it very accurate anyways.

    Is this the issue, or am I way off the mark?

    • GarageWoodworks says:

      I’m thinking that with repetitive sharpening the knives might get different widths. This would result inthe highest set knife doing most of the cutting. If I elongate the holes on the knives and make a setting jig, I could have them protruding by the same distance. We’ll see. No way I’m buying new knives each time they get dull.

  3. Joe says:

    I think it would work. Planers that have springs behind the knives don’t seem to have a problem with the knives moving, and the 735 has just as many (if not more) clamping screws.

    A setting jig might be easier to use on the 735 because you’re working from above, and the cylinder has indexing pins to hold it in place while adjusting/tightening the blades. The downside is that I can’t quite visualize what the jig would look like, but where there is a will there is a way.

  4. Keith says:

    It’s hard to see in your second picture, but is the bevel on that blade facing up or down? The manual appears to have the bevel facing up – meaning the wide part of the blade faces down toward the cutter head and the narrower side of the blade (due to the bevel) faces up. I think I have my blades installed correctly, but I’m having trouble with it and want to double check blade/knife orientation.

    thanks

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